Resistive memory array using P-I-N diode select device and methods of fabrication thereof

ABSTRACT

An electronic structure includes a resistive memory device, and a P-I-N diode in operative association with the resistive memory device. A plurality of such electronic structures are used in a resistive memory array, with the P-I-N diodes functioning as select devices in the array. Methods are provided for fabricating such resistive memory device-P-I-N diode structures.

BACKGROUND OF THE INVENTION

1. Technical Field

This invention relates generally to resistive memory arrays, and moreparticularly, to fabrication and use of P-I-N diodes as part of thearray.

2. Background Art

FIG. 1 illustrates a resistive memory array 60. The array 60 includes afirst plurality of parallel conductors 62 (bit lines) BL0, BL1, . . .BLn, and a second plurality of parallel conductors 64 (word lines) WL0,WL1, . . . WLn overlying and spaced from, orthogonal to, and crossingthe first plurality of conductors 62. A plurality of memory structures66 are included in the array. Each memory structure 66 includes aresistive memory cell 68 and a diode 70 in series therewith connecting aconductor WL of the plurality thereof with a conductor BL of theplurality thereof at the intersection of those conductors, with thediode 70 in a forward direction from the conductor WL to the conductorBL. For example, as shown in FIG. 1, in the memory structure 66 ₀₀,resistive memory cell 68 ₀₀ and diode 70 ₀₀ connect in series WL0 withBL0; in the memory structure 66 ₀₁, resistive memory cell 68 ₀₁ anddiode 70 ₀₁ connect in series connect WL1 with BL0, etc.

The diodes 70 have the conventional PN configuration shown in FIGS. 2and 3, including a P+ region in contact with an N+ region. As is wellknown, a diode of this type, having a relatively low forward thresholdvoltage, readily conducts current in the forward direction uponapplication of forward potential thereto (FIG. 2), but having arelatively high reverse breakdown voltage, does not conduct substantialcurrent upon application of reverse potential thereto (FIG. 3).

Because of this characteristic, these diodes 70 (oriented as shown inFIGS. 1, 4 and 5) are used as select devices in the array 60 of FIG. 1.FIGS. 1, 4 and 5 illustrate this utility.

FIG. 1 illustrates the programming of a selected resistive memory cell68 ₀₀ of the array 60. In such programming, V_(pg) is applied to wordline WL0, and 0V is applied to bit line BL0 and word lines WL1 . . .WLn. Meanwhile, V_(pg) is applied to bit lines BL1 . . . BLn. Thiscauses a voltage V_(pg) to be applied across the memory structure 66 ₀₀,in the forward direction from the word line WL0 to the bit line BL0,sufficient to program the resistive memory cell 68 ₀₀. All otherresistive memory cells connected to the word line WL0 and bit line BL0have 0V potential thereacross. Meanwhile, all the other resistive memorycells of the array 60 have V_(pg) applied thereacross in the reversedirection of the diode 70, with V_(pg) applied thereto being less thanthe reverse breakdown voltage of the diode 70. In this way, the diodesthroughout the array 60 act as select devices to ensure that only theselected resistive memory cell is programmed and that the otherresistive memory cells of the array are undisturbed.

FIG. 4 illustrates the erasing of the selected resistive memory cell 68₀₀ of the array 60. In such erasing, V_(er) (lower voltage than V_(pg))is applied to word line WL0, and 0V is applied to bit line BL0 and wordlines WL1 . . . WLn. Meanwhile, V_(er) is applied to bit lines BL1 . . .BLn. This causes a voltage V_(er) to be applied across the memorystructure 66 ₀₀, in the forward direction from the word line WL0 to thebit line BL0, which (along with increased current applied through theresistive memory cell 68 ₀₀ as compared to programming current) issufficient to erase the resistive memory cell 68 ₀₀. All other resistivememory cells connected to the word line WL0 and bit line BL0 have 0Vpotential thereacross. Meanwhile, all the other resistive memory cellsof the array 60 have V_(er) applied thereacross in the reverse directionof the diode 70, with V_(er) applied thereto being less than the reversebreakdown voltage of the diode. In this way, the diodes throughout thearray 60 act as select devices to ensure that only the selectedresistive memory cell is erased and that the other resistive memorycells of the array are undisturbed.

FIG. 5 illustrates the reading of the selected resistive memory cell 68₀₀ of the array 60. In such reading, V_(r) (lower voltage than V_(er))is applied to word line WL0, and 0V is applied to bit line BL0 and wordlines WL1 . . . WLn. Meanwhile, V_(r) is applied to bit lines BL1 . . .BLn. This causes a voltage V_(r) to be applied across the memorystructure 66 ₀₀, in the forward direction from the word line WL0 to thebit line BL0, sufficient to read the state of the resistive memory cell68 ₀₀. All other resistive memory cells connected to the word line WL0and bit line BL0 have 0V potential thereacross. Meanwhile, all the otherresistive memory cells of the array 60 have V_(r) applied thereacross inthe reverse direction of the diode 70, with V_(r) applied thereto beingless than the reverse breakdown voltage of the diode. In this way, thediodes throughout the array 60 act as select devices to ensure that onlythe selected resistive memory cell is read and that the other resistivememory cells of the array are undisturbed.

While such an approach is useful, it will be understood that diodes ofthis type may exhibit an undesirable degree of current leakage,potentially resulting in undesired disturbing of other cells, along witha high level of power consumption. Meanwhile, it will be understooddiodes used as select devices should provide high driving capability.What is needed is an approach wherein select devices in a resistivememory array exhibit very low current leakage along with high drivingcapability. What is further needed are methods for fabricatingstructures which are capable of providing these features, which methodsare simple and efficient.

DISCLOSURE OF THE INVENTION

Broadly stated, the present method of forming a region of a P-I-N diodecomprises providing a semiconductor body, providing a doped bodyadjacent the semiconductor body, the doped body containing a dopant of aselected conductivity type, and diffusing dopant of the selectedconductivity type from the doped body into the semiconductor body toform a region of the selected conductivity type in the semiconductorbody, the region of the selected conductivity type in the semiconductorbody making up part of a P-I-N diode.

The present invention is better understood upon consideration of thedetailed description below, in conjunction with the accompanyingdrawings. As will become readily apparent to those skilled in the artfrom the following description, there are shown and describedembodiments of this invention simply by way of the illustration of thebest mode to carry out the invention. As will be realized, the inventionis capable of other embodiments and its several details are capable ofmodifications and various obvious aspects, all without departing fromthe scope of the invention. Accordingly, the drawings and detaileddescription will be regarded as illustrative in nature and not asrestrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features believed characteristic of the invention are setforth in the appended claims. The invention itself, however, as well assaid preferred mode of use, and further objects and advantages thereof,will best be understood by reference to the following detaileddescription of illustrative embodiments when read in conjunction withthe accompanying drawings, wherein:

FIG. 1 illustrates programming of a resistive memory cell of a prior artresistive memory array;

FIGS. 2 and 3 illustrate a prior art diode as used in the array of FIG.1;

FIG. 4 illustrates erasing of a resistive memory cell of the resistivememory array of FIG. 1;

FIG. 5 illustrates reading of a resistive memory cell of the resistivememory array of FIG. 1;

FIGS. 6-23 illustrate method steps in fabricating a first embodiment ofdiode and resistive memory device in accordance with the presentinvention;

FIGS. 24-41 illustrate method steps in fabricating a second embodimentof diode and resistive memory device in accordance with the presentinvention;

FIGS. 42-54 illustrate method steps in fabricating a third embodiment ofdiode and resistive memory device in accordance with the presentinvention;

FIGS. 55 and 56 illustrate the present P-I-N diode and its operatingcharacteristics;

FIG. 57 illustrates programming, erasing and reading of a resistivememory cell of the present memory array incorporating the present P-I-Ndiodes;

FIGS. 58 and 59 illustrate devices in relation to feature size; and

FIGS. 60-62 illustrate systems using devices of the previousembodiments.

BEST MODE(S) FOR CARRYING OUT THE INVENTION

Reference is now made in detail to specific embodiments of the presentinvention which illustrate the best mode presently contemplated by theinventors for practicing the invention.

Referring to FIG. 6, a monocrystalline P− silicon semiconductorsubstrate 100 is provided. A silicon nitride (Si₃N₄) layer 102 isdeposited thereon, and using standard photolithographic techniques,silicon nitride strips 102A, 102B (running perpendicular to the plane ofthe drawing of FIG. 6) are formed. Using the silicon nitride strips102A, 102B as a mask, the semiconductor substrate 100 is etched to formopenings 104A, 104B, 104C therein and to define elongated siliconsemiconductor strips 106A, 106B (FIG. 7). Next (FIG. 8), a High DensityPlasma (HDP) undoped oxide 108A, 108B, 108C is deposited in the openings104A, 104B, 104C, and a chemical mechanical polish (CMP) is undertakento planarize the top surface of the resulting structure. Referring toFIG. 9, a substantial portion of the HDP oxide 108A, 108B, 108C isremoved by etching from each of the openings 104A, 104B, 104C, leaving asmaller portion of HDP oxide 108D, 108E, 108F at the bottom thereof.Then, an N+, for example phosphorus doped oxide 110A, 110B, 110C isdeposited in each of the remaining openings 104A, 104B, 104C, and achemical mechanical polish is undertaken to planarize the top surface ofthe resulting structure.

Referring to FIG. 10, a portion of the phosphorus doped oxide 110A,110B, 110C is removed from each of the openings 104A, 104B, 104C,leaving smaller portions 110D, 110E, 110F thereof in each of theopenings 104A, 104B, 104C on the remaining HDP oxide portions 108D,108E, 108F respectively. HDP (undoped) oxide 112A, 112B, 112C is thendeposited in the openings 104A, 104B, 104C, and a chemical mechanicalpolish is undertaken to planarize the top surface of the resultingstructure.

Then, high temperature is applied to the resulting structure, causingphosphorus dopant to simultaneously diffuse from each of the phosphorusdoped oxide portions 110D, 110E, 110F into the adjacent silicon strips106A, 106B on opposite sides thereof. That is, as will be seen in FIG.11, dopant simultaneously flows and diffuses from the portion 110Ebetween the silicon strips 106A, 106B into both of those silicon strips106A, 106B. Likewise, dopant simultaneously flows and diffuses from theportion 110D into the silicon strip 106A and into the silicon strip onthe opposite side thereof (not shown), and simultaneously dopant flowsand diffuses from the portion 110F into the silicon strip 106B and intothe silicon strip on the opposite side thereof (not shown). In this way,N+ regions 114A, 114B are formed in the silicon strips 106A, 106B,extending across the strips, with intrinsic regions 116A, 116Brespectively thereover.

Next, all material is removed from between the silicon strips (FIG. 12),HDP (undoped) oxide 118A, 118B, 118C is deposited in the openings 104A,104B, 104C (FIG. 13), and a chemical-mechanical polish is undertaken.FIG. 14 shows the resulting structure as viewed along the line 14-14 ofFIG. 13.

Using standard photolithographic masking and etching techniques, thesilicon nitride layer 102A is patterned as shown in FIG. 15, formingrectangular silicon nitride bodies 102A1, 102A2, and an etching step isundertaken to etch away the unmasked portions of silicon down to the N+region 114A to form pillars 116A1, 116A2 of silicon material. Openingsare filled with undoped HDP oxide 119 (FIG. 16), and achemical-mechanical polish is undertaken. Next, the silicon nitride102A1, 102A2 (and portions of the exposed HDP oxide 119) are removed,and an ion implant is undertaken, implanting for example boron into theexposed portions of the silicon pillars 116A1, 116A2, to simultaneouslyform P+ regions 120A, 120B therein, to a depth so that in each pillar,there is defined an intrinsic region between the P+ region thereof andthe N+ region (intrinsic region 121A between P+ region 120A and N+region 114A; intrinsic region 121B between P+ region 120B and N+ region114A, FIG. 17). An activation step is than undertaken.

As an alternative, instead of implanting dopant into the pillars to formthe P+ regions, a layer of P+ (for example boron) doped oxide 122 may bedeposited over the structure of FIG. 17 prior to implant, with a hightemperature step being undertaken to simultaneously diffuse dopant fromthe oxide layer 122 into the pillars 116A1, 116A2 to form the P+ regions(FIG. 19). The layer 122 is then removed and an activation step isundertaken.

Next, a metal layer 124, for example cobalt, tantalum, nickel, titanium,platinum, palladium, tungsten, or hafnium is deposited over theresulting structure (FIG. 20) and (FIG. 21) a silicidation step isundertaken to form metal silicide regions 126A, 126B on the exposedsilicon. The metal on the oxide does not react therewith and is removedafter the silicidation step. Next, an insulating layer 128 is depositedover the resulting structure, and a metal layer 130 is deposited overthe insulating layer 128 (FIG. 22). Using conventional masking andetching techniques, the metal layer 130 is formed into strips 132A, 132Brunning perpendicular to the plane of the drawing of FIG. 22 (see FIG.23).

In this embodiment, the elongated N+ regions 114A, 114B form bit linesof the array 460 of FIG. 57. As will be seen, a plurality of P-I-Ndiodes are formed, each connected in series with a resistive memorydevice. Each P-I-N diode includes an N+ region, an intrinsic (I) region,and a P+ region, in stacked relation. In contact with each P+ region isa silicide. On and in contact with this silicide is an insulating layer,and on and in contact with this insulating layer are metal strips. As anexample, the silicide 126A, insulating layer 128, and metal strip 132Atogether form the respective first electrode, insulating layer, andsecond electrode of a metal-insulator-metal (MIM) resistive memorydevice 140 connected in series with the respective P-I-N diode 142(including P+ region 120A, intrinsic region 121A, and N+ region 114A)associated therewith. The metal strips 132A, 132B form the word lines ofthe array 460 of FIG. 57.

In a second embodiment of the invention, referring to FIG. 24, amonocrystalline P− silicon semiconductor substrate 200 is provided.Using appropriate masking techniques, an N+ ion blanket implant, forexample phosphorous, is undertaken, at for example 5E15 keV, to form N+region 202. A silicon nitride (Si₃N₄) layer is then deposited over theresulting structure and, using appropriate masking techniques, thesilicon nitride layer is patterned into strips 204A, 204B, 204C runningperpendicular to the plane of the drawing of FIG. 25. Using the siliconnitride strips 204A, 204B, 204C as a mask, the N+ region 202 is etchedto form openings 206A, 206B, 206C therein (FIG. 26) and to defineelongated N+ regions 202A, 202B in the form of strips runningperpendicular to the plane of the drawing of FIG. 26. Next (FIG. 27),HDP undoped oxide 208A, 208B, 208C is deposited in the openings 206A,206B, 206C, and a chemical mechanical polish (CMP) is undertaken toplanarize the top surface of the resulting structure. Referring to FIG.28, a substantial portion of the HDP oxide 208A, 208B, 208C is removedby etching, leaving a smaller portion of HDP oxide 208D, 208E, 208F. Ametal layer 210, for example cobalt, tantalum, nickel, titanium,platinum, palladium, tungsten, or hafnium is deposited over theresulting structure (FIG. 28), and (FIG. 29) a silicidation step isundertaken to form metal silicide regions 212A, 212B, 212C, 212D, 212Eon the sides of the exposed silicon. The metal on the oxide and nitridedoes not react therewith and the unreacted metal is removed after thesilicidation step.

Next (FIG. 30), HDP undoped oxide 214A, 214B, 214C is deposited in theopenings 206A, 206B, 206C, and a chemical mechanical polish (CMP) isundertaken to planarize the top surface of the resulting structure. Thesilicon nitride 204A, 204B, 204C is then removed (FIG. 31), and theopenings over the exposed silicon (including N+ strips 202A, 202B) arefilled with HDP oxide 216A, 216B, 216C (FIG. 32).

FIG. 33 as a view taken along the line 33-33 of FIG. 32. The oxide stripon each of the N+ regions is patterned as shown in FIG. 34 (oxide strip216A patterned as 216A1, 216A2, 216A3 and N+ region 202A shown in FIG.34), using appropriate masking technology. This patterning of the oxide216A provides rectangular openings therethrough on and over theassociated N+ strip 202A, the openings being configured as shown in FIG.35 along the length of the associated N+ strip 202A and substantiallyequal in width to the associated N+ strip 202A. Monocrystallineepitaxial silicon layers 218A, 218B are then grown on the exposedsilicon, rectangular in configuration, and filling the openings in theoxide layer 216A (FIG. 35). Similar to the previous embodiment, an ionimplant and activation is undertaken, implanting for example boron intothe exposed portions of the epitaxial silicon 218A, 218B, tosimultaneously form P+ region 221A, 221B respectively therein, to adepth so that in each epitaxial layer, there is defined an intrinsicregion 220A, 220B respectively between the P+ region thereof and the N+region (FIG. 35).

FIG. 36 is a view of the structure of FIG. 35, taken from the positionin viewing FIGS. 24-32. Referring to FIG. 37, using appropriatelypatterned photoresist 224A, 224B, 224C as masking to block off oppositeedges of each P+ region and to leave exposed a central portion thereof,an implant of O₂ is undertaken into the exposed P+ regions 221A, 223A toform O₂-implanted regions 225, 226. After removal of the photoresist224A, 224B, 224C, a metal layer 227, for example, cobalt, tantalum,nickel, titanium, platinum, palladium, tungsten, or hafnium is depositedover the resulting structure (FIG. 38) and (FIG. 39, and FIG. 40, a viewtaken along the line 40-40 of FIG. 39) a silicidation step is undertakento form metal silicide regions 228A, 228B, 228C, 228D on the exposedsilicon. The metal on the oxide and on the O₂-implanted silicon 225, 226does not react therewith and the unreacted metal is removed after thesilicidation step.

Next, an insulating layer 230 is deposited over the resulting structure,and a metal layer 232 is deposited over the insulating layer 230 (FIG.41). Using conventional etching techniques, the metal layer 232 isformed into strips running parallel to the plane of the drawing of FIG.41.

In this embodiment, the elongated N+ regions 202A, 202B form bit linesof the array 460 of FIG. 57. As will be seen, a plurality of P-I-Ndiodes are formed, each connected in series with a resistive memorydevice. Each P-I-N diode includes an N+ region, an intrinsic (I) region,and a P+ region. In contact with each P+ region is a silicide. On and incontact with this silicide is an insulating layer, and on and in contactwith this insulating layer are metal strips. As an example, the silicide228A, insulating layer 230, and metal strip 232 together form therespective first electrode, insulating layer, and second electrode of ametal-insulator-metal (MIM) resistive memory device connected in serieswith the respective P-I-N diode (221A, 220A, 202A) associated therewith.The metal strips 232 form the word lines in the array 460 of FIG. 57.

The silicide regions 212A, 212B, 212C, 212D, 212E on each N+ strip actas low resistance conductors connecting that N+ region with itsassociated intrinsic region.

In a third embodiment of the invention, referring to FIG. 42, thestructure formed is similar to that of FIG. 9, including monocrystallinesubstrate 300, oxide regions 308A, 308B, N+ (for example phosphorus)doped oxide regions 310A, 310B, silicon strips 306A, 306B, and siliconnitride strips 302A, 302B, 302C. At this point in the process, hightemperature is applied to the resulting structure, causing phosphorusdopant to simultaneously diffuse from each of the phosphorus doped oxideportions into the adjacent silicon strips on opposite sides thereof. Inthis way, N+ regions 314A, 314B, 314C, 314D, 314E are formed, thediffusion being controlled and limited so that an intrinsic portionremains between the N+ regions formed in each silicon strip (316A, 316Bshown). An N+ activation step is then undertaken.

Next, portions of the phosphorus doped oxide 310A, 310B are removed,leaving smaller portions 310C, 310D on the HDP oxide 308A, 308B, and ametal layer 318, for example cobalt, tantalum, nickel, titanium,platinum, palladium, tungsten, or hafnium is deposited over theresulting structure (FIG. 43). A silicidation step is undertaken to formmetal silicide regions 320A, 320B, 320C, 320D, 320E on the exposedsilicon. The metal on the oxide and nitride does not react therewith andthe unreacted metal is removed after the silicidation step. The N+ oxideand oxide regions 308A, 308B are then removed, and the remainingopenings are filled with (undoped) HDP oxide 322A, 322B (FIG. 44).

Then (FIG. 45), successive layers of N+ (for example phosphorous) dopedoxide 330, undoped oxide 332, and P+ (for example boron) doped oxide 334are applied and etched to form strips 335A, 335B running on and alongthe oxide 322A, 322B therebeneath (FIG. 46), the strips 335A, 335Brunning perpendicular to the plane of the drawing of FIG. 46. Referringto FIG. 47, monocrystalline silicon epitaxial layers 336A, 336B, 336C inthe form of strips are then grown on the exposed silicon. Next, hightemperature is applied to the resulting structure, causing dopant tosimultaneously flow and diffuse from portions between the epitaxialstrips into both of those epitaxial strips, to simultaneously form apair of P+ regions in each of the silicon strips and a pair of N+regions in each of the epitaxial strips. The P+ regions in each stripare separated by an intrinsic region, and the N+ regions in each stripare separated by an intrinsic region. The P+ and N+ regions adjacent theN+ doped oxide, undoped oxide, and P+ doped oxide are separated by anintrinsic region. For example, dopant flows from doped oxide region 334Ainto the adjacent epitaxial layer 336A and the adjacent epitaxial layer336B to form P+ regions 340 and 342 respectively therein. At the sametime, dopant flows from doped oxide region 330A into the adjacentepitaxial layer 336A and the adjacent epitaxial layer 336B to form N+regions 344 and 346 respectively therein. Likewise, dopant flows fromdoped oxide region 334B into the adjacent epitaxial layer 336B and theadjacent epitaxial layer 336C to form P+ regions 348 and 350respectively therein. At the same time, dopant flows from doped oxideregion 330B into the adjacent epitaxial layer 336B and the adjacentepitaxial layer 336C to form N+ regions 352 and 354 respectivelytherein. Intrinsic regions 11, 12 remain as shown. All of these P+ andN+ regions are formed simultaneously. Then, an activation step is thenundertaken.

Next (FIG. 48), the strips 335A, 335B and oxide 322A, 322B are removedand the resulting openings are filled with undoped HDP oxide 338A, 338B.FIG. 49 shows the resulting structure of FIG. 48 taken along the line49-49 of FIG. 48.

As shown in FIG. 50, photoresist is applied to the resulting structureand is patterned as shown in that Figure (360A, 360B, 360C). An etchingstep is undertaken, using the photoresist as a mask, to form pillars362, 364, 366, respectively including N+ regions 346A, 346B, 346C,intrinsic regions I2A, I2B, I2C, and P+ regions 342A, 342B, 342C (FIG.51). The photoresist is removed, and the resulting openings are filledwith undoped HDP oxide 363A, 363B (FIG. 52). FIG. 53 is a view of thestructure of FIG. 52 as viewed in a manner similar to the previous FIGS.42-48. Similar to the previous embodiments, a metal layer 370 isdeposited and patterned, and a silicidation step is undertaken to formsilicide regions 372A, 372B, 372C, 372D, 372E in contact with therespective P+ regions. An insulating layer 374 is deposited thereover,and a metal layer 376 is deposited on the insulating layer 374 and ispatterned to provide strips running parallel to the plane of the drawingof FIG. 54.

In this embodiment, the elongated N+ regions 314A, 314B, 314C, 314D,314E form the bit lines of the array 460 of FIG. 57. As will be seen, aplurality of P-I-N diodes are formed. Each includes an N+ region, anintrinsic (I) region, and a P+ region. In contact with each P+ region isa silicide. On and in contact with this silicide region is an insulatinglayer, and on and in contact with this insulating are the metal strips.As an example, the silicide 372B, insulating layer 374, and metal strip376 together form the respective first electrode, insulating layer, andsecond electrode of a metal-insulator-metal (MIM) resistive memorydevice connected in series with the respective P-I-N diode (340, I1,344) associated therewith. The metal strips 376 form the word lines inthe array 460 of FIG. 57.

The silicide regions 320A, 320B, 320C, 320D, 320E on each N+ region actas low resistance conductors connecting that N+ region with itsassociated P-I-N diode.

FIGS. 55 and 56 illustrate the structure and operating characteristicsof a P-I-N diode formed in accordance with the above methods. As shownin FIG. 55, the P-I-N diode includes N+ region and P+ region separatedby an intrinsic region 1. As illustrated in FIG. 56, with the diodeforward biased (higher potential applied to P+ region than to N+ region,+V), current flows in the forward direction through the diode, with thediode exhibiting decreasing resistance with increasing current, as istypical with the P-I-N diode configuration. Meanwhile, such a diodeexhibits a high reverse breakdown voltage (higher potential applied toN+ region than to P+ region, −V).

FIG. 57 illustrates a resistive memory array 460 incorporating thepresent invention. The array 460 includes a first plurality of parallelconductors 462 (bit lines) BL0, BL1, . . . BLn, and a second pluralityof parallel conductors 464 (word lines) WL0, WL1, . . . WLn overlyingand spaced from, orthogonal to, and crossing the first plurality ofconductors 462. A plurality of memory structures 466 are included in thearray 460. Each memory structure 466 includes a resistive memory cell468 (including as shown for resistive memory cell 468 ₀₀ a firstelectrode 490, insulating layer 492 on and in contact with firstelectrode 490, and second electrode 494 on and in contact with theinsulating layer 492), and a diode 470 in series therewith connecting aconductor WL of the plurality thereof with a conductor BL of theplurality thereof at the intersection of those conductors, with thediode thereof oriented in a forward direction from the conductor WL tothe conductor BL. These memory structures 466 take the various formsshown and described above, including any of the various forms of P-I-Ndiode. The P-I-N diode characteristics insure that the diodes allow forproper programming, erasing and reading of a selected memory device(application of V_(pg), V_(er) and V_(r) as previously shown anddescribed), meanwhile acting as select devices for other memory devicesin the array 460 so as to avoid disturbing the state thereof. The diodesexhibit very low current leakage and high drivability. In addition, itwill be noted that in each embodiment only two masking steps arerequired to fabricate the P-I-N diodes, resulting in high efficiency inthe manufacturing process.

In the interest of forming an overall structure of very high density,the pillars in all embodiments are with advantage formed using minimumfeature size F. This minimum feature size F also determines the spacebetween adjacent pillars in the horizontal and vertical directions(FIGS. 58 and 59). The unit block A of FIGS. 58 and 59, dimensions 2F×2F(dark lined box), including a pillar (dark hatching) and three adjacentspaces, repeats itself across the overall structure. Each block(including the indicated unit block A) has an area 2F×2F=4F². Thus,where each pillar includes a single P-I-N diode and a single memorydevice associated therewith (i.e., the embodiments of FIGS. 6-23 andalso FIG. 58, pillar 116A2 illustrated in unit block A), one P-I-N diodeand one memory device are provided for each area 4F².

Device density is improved where each pillar includes two P-I-N diodes,with two memory device associated therewith (i.e., the embodiments ofFIGS. 24-54 and also FIG. 59, illustrating pillar 364 in unit block A).As such, two P-I-N diodes and two memory device are provided for eacharea 4F², i.e., one P-I-N diode and one associated memory device foreach area 2F² (4F²/2). This approach, it will be seen, provides improvedscaling through increased devices density.

FIG. 60 illustrates a system 500 utilizing devices as described above.As shown therein, the system 500 includes hand-held devices in the formof cell phones 502, which communicate through an intermediate apparatussuch as a tower 504 (shown) and/or a satellite. Signals are providedfrom one cell phone to the other through the tower 504. Such a cellphone 502 with advantage uses devices of the type described above. Oneskilled in the art will readily understand the advantage of using suchdevices in other hand-held devices.

FIG. 61 illustrates another system 600 utilizing devices as describedabove. The system 600 includes a vehicle 602 having an engine 604controlled by an electronic control unit 606. The electronic controlunit 606 with advantage uses devices of the type described above.

FIG. 62 illustrates yet another system 700 utilizing devices asdescribed above. This system 700 is a computer 702 which includes aninput in the form of a keyboard, and a microprocessor for receivingsignals from the keyboard through an interface. The microprocessor alsocommunicates with a CDROM drive, a hard drive, and a floppy drivethrough interfaces. Output from the microprocessor is provided to amonitor through an interface. Also connected to and communicating withthe microprocessor is memory which may take the form of ROM, RAM, flashand/or other forms of memory. The memory and other parts of the computer702 with advantage use devices of the type described above.

The foregoing description of the embodiments of the invention has beenpresented for purposes of illustration and description. It is notintended to be exhaustive or to limit the invention to the precise formdisclosed. Other modifications or variations are possible in light ofthe above teachings.

The embodiments were chosen and described to provide the bestillustration of the principles of the invention and its practicalapplication to thereby enable one of ordinary skill of the art toutilize the invention in various embodiments and with variousmodifications as are suited to the particular use contemplated. All suchmodifications and variations are within the scope of the invention asdetermined by the appended claims when interpreted in accordance withthe breadth to which they are fairly, legally and equitably entitled.

1. A method of forming regions of a P-I-N diode comprising: providing asemiconductor body; providing first and second doped bodies adjacent andrunning along opposite sides of the semiconductor body, the first andsecond doped bodies containing a dopant of a first selected conductivitytype; providing a third doped body overlying the semiconductor body, thethird doped body containing a dopant of a second selected conductivitytype opposite the first selected conductivity type; diffusing dopant ofthe first selected conductivity type from the first and second dopedbodies into the semiconductor body to form a first region of the firstselected conductivity type in the semiconductor body, the first regionof the first selected conductivity type in the semiconductor body makingup part of a P-I-N diode; diffusing dopant of the second selectedconductivity type from the third doped body into the semiconductor bodyto form a region of the second selected conductivity type in thesemiconductor body, the region of the second selected conductivity typein the semiconductor body making up part of a P-I-N diode; and diffusingdopant of the first selected conductivity type from the first and seconddoped bodies into the semiconductor body to form the first region and asecond region of the first selected conductivity type in thesemiconductor body, the second region making up part of a P-I-N diode.2. The method of claim 1 wherein the first region of the first selectedconductivity type and the region of the second selected conductivitytype are formed at different times in the semiconductor body.
 3. Themethod of claim 1 wherein an intrinsic region is provided between thefirst region of the first selected conductivity type and the region ofthe second selected conductivity type.
 4. The method of claim 1 whereinthe semiconductor body comprises monocrystalline material.
 5. The methodof claim 4 wherein the semiconductor body comprises epitaxial material.6. The method of claim 1 and further comprising providing a conductor incontact with the first region of the selected conductivity type in thesemiconductor body making up part of a P-I-N diode.
 7. The method ofclaim 6 wherein the conductor is a silicide.
 8. The method of claim 1and further comprising: providing a second semiconductor body, thesecond doped body and a third doped body being adjacent the secondsemiconductor body, wherein the second and third doped bodies run alongopposite sides of the second semiconductor body; and diffusing dopant ofthe first selected conductivity type from the second and third dopedbodies into the second semiconductor body to form a first region of thefirst selected conductivity type in the second semiconductor body, thefirst region of the first selected conductivity type in the secondsemiconductor body making up part of a P-I-N diode.
 9. The method ofclaim 8 wherein the second semiconductor body comprises monocrystallinematerial.
 10. The method of claim 9 wherein the second semiconductorbody comprises epitaxial material.
 11. The method of claim 8 and furthercomprising providing a conductor in contact with a region of the firstselected conductivity type in the second semiconductor body making uppart of a P-I-N diode.
 12. The method of claim 11 wherein the conductoris a silicide.
 13. The method of claim 1 wherein an intrinsic region isprovided between the first and second regions of the first selectedconductivity type.
 14. The method of claim 13 wherein the first andsecond regions of the first selected conductivity type are formedsimultaneously in the semiconductor body.
 15. The method of claim 13wherein the semiconductor body comprises monocrystalline material. 16.The method of claim 15 wherein the semiconductor body comprisesepitaxial material.
 17. The method of claim 1 and further comprisingproviding a conductor in contact with a region of the first selectedconductivity type in the semiconductor body making up part of a P-I-Ndiode.
 18. The method of claim 17 wherein the conductor is a silicide.19. The method of claim 1 and further comprising forming a resistivememory device associated with the resulting structure.
 20. The method ofclaim 19 wherein the resistive memory device comprises a firstelectrode, an insulating layer on and in contact with the firstelectrode, and a second electrode on and in contact with the insulatinglayer.
 21. The method of claim 1 and further comprising said P-I-N diodeincorporated in a system.
 22. The method of claim 21 wherein the systemis selected from the group consisting of a hand-held device, a vehicle,and a computer.
 23. A method of forming a P-I-N diode comprising:providing a first and second semiconductor body; providing first andsecond doped bodies adjacent the first semiconductor body and a thirddoped body and the second doped body adjacent the second semiconductorbody, the first, second, and third doped bodies containing a dopant of afirst selected conductivity type, wherein the first and second dopedbodies run along opposite sides of the first semiconductor body, andwherein the second and third doped bodies run along opposite sides ofthe second semiconductor body; and diffusing dopant of the firstselected conductivity type from the first and second doped bodies andthe second and third doped bodies into the first and secondsemiconductor bodies, respectively, to form a region of the firstselected conductivity type in the first and second semiconductor bodies,the regions of the first selected conductivity type in the first andsecond semiconductor bodies each making up part of a P-I-N diode. 24.The method of claim 23, further comprising: providing a third doped bodyoverlying the first semiconductor body and a fourth doped body overlyingthe second semiconductor body, the third and fourth doped bodies eachcontaining a dopant of a second selected conductivity type opposite thefirst selected conductivity type; and diffusing dopant of the secondselected conductivity type from the third and fourth doped bodies intothe first and second semiconductor bodies, respectively, to form aregion of the second selected conductivity type in the first and secondsemiconductor bodies, the regions of the second selected conductivitytype in the first and second semiconductor bodies each making up part ofa P-I-N diode.